Vertex Piston in a 2001 YZ125

[MRKRacing125]

Well, its almost time for another top-end kit (NOT AGAIN). Do any of you guys have any tips on pistons? I have been using just the standerd OEM Piston kit, and I think I am going to try and wonder off the path of OEM. Anyone find any real results from different pistons? Vertex? Pro-X? Wiesco?

 

[MXP1MP]

My friend who has an '01 runs the wiseco "GP" piston . I've seen one of his old ones and its a nice piston, does not have the lightening holes and no piston port window I think it also has less clearance also. It is definetly a heavier piston than the OEM unit is. I know it must be a good piston my friend races pro class and thats all he'll use. I'm going to be putting one in my '02 soon. I know vertex pistons are good but its alot like the oem unit there sold more as oem replacements? don't quote me on that. I heard they wear longer cause of the coating. But it would definetly be my other choice with a top end kit. motoworldracing.com is selling complete OEM top end kits for alittle under $80.

 

[marcusgunby]

Apart from on a Cr which has a really loose std piston you probably wont notice much difference between any other pistons in terms of performance, saying that the one area to look as is as MXPIMP pointed out-some pistons come without windows/lightening holes, this generally is done for more bottom end but may sacrifice top end to get it.If you are after a trade in bottom for top then look into one of these type pistons from wiseco/vertex, if not get the std type piston from vertex or wiseco-both are very good and should last better than the OEM set up.

 

[Brett]

Im not positive this is corect but I heard this. On the vertex pistons the coating is only a good thing because it aids in the break in, the coating wears off very quick and it becomes just like any other "non-coated" piston?

 

[Durt Cycler]

I'm running a Vertex Race piston in my CR and now just with 30mins of break-in time on the stand I don't really believe the coating gives it any advantiges over OEM or other aftermarketpistons. The coating on my piston skirt is still as it was brand new and the only good thing about it is every once and awhile I will remove my pipe and reed cage and look for any scatches or scoring in the coating. :)

 

[yamaha1]

Aren't Wiseco pistons forged pistons? Don't forged piston reguire more careful break-in and warm-up? I have heard a lot of bad mouthing of Wiseco on DRN, but I had good luck with them in my Gorr KX 268. Any other input on the cast vs. forged debate. Are Vertex, Pro-X, and OEM all cast pistons?

 

[Durt Cycler]

Originally posted by yamaha1
Aren't Wiseco pistons forged pistons? Don't forged piston reguire more careful break-in and warm-up? I have heard a lot of bad mouthing of Wiseco on DRN, but I had good luck with them in my Gorr KX 268. Any other input on the cast vs. forged debate. Are Vertex, Pro-X, and OEM all cast pistons?

1. Yes Wiseco are forged.
2. About 30 minutes of break-in time on Wiseco pistons and your done.
3. OEM, Vertex are cast and I "think" Pro-X along with Wiseco are forged.

Cast pistons give you more life out of them then forged but are heavier then forged.

I hope I'm right and don't sound like a idiot....:o

 

[marcusgunby]

cast pistons last less well than forged but are generally lighter :moon:

 

[JohninKY]

How does a heavier piston make for more bottom end? Seems like you would loose power everywhere from accelerating the extra mass. I would guess the motor would rev slower maybe giving you a gain in traction like a flywheel weight?

 

[mudronin]

If memory serves me correctly, the pro-x are cast but they are hi-silica pressure treated units sometimes <in cars at least> called hyper-eutectic. I ran trw's myself and their design allowed for much tighter tolerances as well as being considerably stronger than cast<tested true with many passes with a 200 shot of nitrous>.

Don't be fooled as they are not forged and after said abuse for 2 summers and ...erm ....some street fun they were ready to be replaced, showing stress fractureson both crown and skirt while one had the wrist pin housing cracked on both ends.
I have no problem with hyper-eutectic. look around as one site will actually describe it in detail....just can't think of which ATM.[